chrome/browser/prerender/prerender_tab_helper.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CHROME_BROWSER_PRERENDER_PRERENDER_TAB_HELPER_H_
   6 #define CHROME_BROWSER_PRERENDER_PRERENDER_TAB_HELPER_H_
   7
   8 #include "base/memory/scoped_ptr.h"
   9 #include "base/time.h"
  10 #include "content/public/browser/web_contents_observer.h"
  11 #include "content/public/browser/web_contents_user_data.h"
  12 #include "googleurl/src/gurl.h"
  13
  14 namespace prerender {
  15
  16 class PrerenderManager;
  17
  18 // PrerenderTabHelper is responsible for recording perceived pageload times
  19 // to compare PLT's with prerendering enabled and disabled.
  20 class PrerenderTabHelper
  21     : public content::WebContentsObserver,
  22       public content::WebContentsUserData<PrerenderTabHelper> {
  23  public:
  24   virtual ~PrerenderTabHelper();
  25
  26   // content::WebContentsObserver implementation.
  27   virtual void ProvisionalChangeToMainFrameUrl(
  28       const GURL& url,
  29       content::RenderViewHost* render_view_host) OVERRIDE;
  30   virtual void DidStopLoading(
  31       content::RenderViewHost* render_view_host) OVERRIDE;
  32   virtual void DidStartProvisionalLoadForFrame(
  33       int64 frame_id,
  34       int64 parent_frame_id,
  35       bool is_main_frame,
  36       const GURL& validated_url,
  37       bool is_error_page,
  38       bool is_iframe_srcdoc,
  39       content::RenderViewHost* render_view_host) OVERRIDE;
  40   virtual void DidCommitProvisionalLoadForFrame(
  41       int64 frame_id,
  42       bool is_main_frame,
  43       const GURL& validated_url,
  44       content::PageTransition transition_type,
  45       content::RenderViewHost* render_view_host) OVERRIDE;
  46   // Called when this prerendered WebContents has just been swapped in.
  47   void PrerenderSwappedIn();
  48
  49  private:
  50   explicit PrerenderTabHelper(content::WebContents* web_contents);
  51   friend class content::WebContentsUserData<PrerenderTabHelper>;
  52
  53   // Helper class to compute pixel-based stats on the paint progress
  54   // between when a prerendered page is swapped in and when the onload event
  55   // fires.
  56   class PixelStats;
  57   scoped_ptr<PixelStats> pixel_stats_;
  58
  59   // Retrieves the PrerenderManager, or NULL, if none was found.
  60   PrerenderManager* MaybeGetPrerenderManager() const;
  61
  62   // Returns whether the WebContents being observed is currently prerendering.
  63   bool IsPrerendering();
  64
  65   // Returns whether the WebContents being observed was prerendered.
  66   bool IsPrerendered();
  67
  68   // System time at which the current load was started for the purpose of
  69   // the perceived page load time (PPLT).
  70   base::TimeTicks pplt_load_start_;
  71
  72   // System time at which the actual pageload started (pre-swapin), if
  73   // a applicable (in cases when a prerender that was still loading was
  74   // swapped in).
  75   base::TimeTicks actual_load_start_;
  76
  77   // Current URL being loaded.
  78   GURL url_;
  79
  80   DISALLOW_COPY_AND_ASSIGN(PrerenderTabHelper);
  81 };
  82
  83 }  // namespace prerender
  84
  85 #endif  // CHROME_BROWSER_PRERENDER_PRERENDER_TAB_HELPER_H_